Caldera
A caldera (/kɔːlˈdɛrə, kæl-/[1] kawl-DERR-ə, kal-) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcanic eruption.
An eruption that ejects large volumes of magma over a short period of time can cause significant detriment to the structural integrity of such a chamber, greatly diminishing its capacity to support its own roof, and any substrate or rock resting above.
[8][6] A collapse is triggered by the emptying of the magma chamber beneath the volcano, sometimes as the result of a large explosive volcanic eruption (see Tambora[9] in 1815), but also during effusive eruptions on the flanks of a volcano (see Piton de la Fournaise in 2007)[10] or in a connected fissure system (see Bárðarbunga in 2014–2015).
[12] As the magma chamber empties, the center of the volcano within the ring fracture begins to collapse.
Metal-rich fluids can circulate through the caldera, forming hydrothermal ore deposits of metals such as lead, silver, gold, mercury, lithium, and uranium.
[11]: 77 For example, when Yellowstone Caldera last erupted some 650,000 years ago, it released about 1,000 km3 of material (as measured in dense rock equivalent (DRE)), covering a substantial part of North America in up to two metres of debris.
[20] Eruptions forming even larger calderas are known, such as the La Garita Caldera in the San Juan Mountains of Colorado, where the 5,000 cubic kilometres (1,200 cu mi) Fish Canyon Tuff was blasted out in eruptions about 27.8 million years ago.
[7] Because a silicic caldera may erupt hundreds or even thousands of cubic kilometers of material in a single event, it can cause catastrophic environmental effects.
Even small caldera-forming eruptions, such as Krakatoa in 1883[28] or Mount Pinatubo in 1991,[29] may result in significant local destruction and a noticeable drop in temperature around the world.
The remnants of such clusters may be found in places such as the Eocene Rum Complex of Scotland,[23] the San Juan Mountains of Colorado (formed during the Oligocene, Miocene, and Pliocene epochs) or the Saint Francois Mountain Range of Missouri (erupted during the Proterozoic eon).
[32] About 74,000 years ago, this Indonesian volcano released about 2,800 cubic kilometres (670 cu mi) dense-rock equivalent of ejecta.
More recently, Lynn Jorde and Henry Harpending proposed that the human species was reduced to approximately 5,000–10,000 people.
Through the use of crewed and uncrewed spacecraft, volcanism has been discovered on Venus, Mars, the Moon, and Io, a satellite of Jupiter.
[40] The Moon has an outer shell of low-density crystalline rock that is a few hundred kilometers thick, which formed due to a rapid creation.
Around 500 million years afterward, the Moon's mantle was able to be extensively melted due to the decay of radioactive elements.
Each province contains a series of giant shield volcanoes that are similar to what we see on Earth and likely are the result of mantle hot spots.
[39] Mars has the tallest volcano in the Solar System, Olympus Mons, which is more than three times the height of Mount Everest, with a diameter of 520 km (323 miles).
